In addition to an ordinary road having a narrow road width, in part of roads, on which high-speed running is allowed, such as an automobile expressway, an urban expressway, a freeway, a general toll highway and a national highway, there is a running section in which a road is divided for each running direction, and the running section is configured such that a vehicle runs only in a predetermined direction. However, when a normal running direction specified for a running section is not clearly shown, a vehicle may be driven in a wrong running direction and may be placed in a so-called wrong-way driving situation where the vehicle runs in a direction opposite to the normal running direction. For example, one of causes that a vehicle is placed in a wrong-way driving situation is that, when a vehicle runs on a one-way traffic road formed of a plurality of lanes, a driver erroneously recognizes that a lane other than the running lane on which the vehicle is running (in the case of left-hand traffic, right-side lane) as an oncoming lane and then makes a U-turn. At an interchange of an expressway or the like, a vehicle is placed in a wrong-way driving situation when the vehicle confuses an exit road from the expressway with an entrance road to the expressway, and then the vehicle wrongly enters the exit road from the expressway. In addition, at the time of returning from a parking lot of a service area or a parking area to a main road, a vehicle may be placed in a wrong-way driving situation when the vehicle confuses an exit road from the main road with an entrance road to the main road, and then the vehicle wrongly enters the exit road from the main road.
In an existing art, a technique which is applied to, for example, a navigation system equipped for the vehicle is suggested for detecting that a vehicle is placed in a wrong-way driving situation because of the above described reasons, or the like. For example, Japanese Patent Application Publication No. 2009-140008 (JP-A-2009-140008) describes a technique that identifies a link, on which a vehicle runs, through map matching process and detects that the vehicle is placed in a wrong-way driving situation when the running direction specified for the identified link does not coincide with the travelling direction of the vehicle.